Each year, 250,000 people in the US suffer strokes that impact their ability to communicate through language (aphasia), and in two-thirds of these cases, recovery is incomplete. Currently, standard treatment for aphasia is limited to speech therapy, but neuromodulation using transcranial direct current stimulation (tDCS) offers a safe, inexpensive adjunct treatment with the potential to boost neural function and recovery. To date, all neuromodulation studies of aphasia have stimulated the lesioned region or the opposite hemisphere, with varying results. Therefore, the optimal site of neuromodulation for post-stroke aphasia has yet to be established. Clinical and neuroimaging evidence suggest that the cerebellum is involved in a variety of language functions, including naming and verbal fluency, which are often impaired in people with aphasia. In particular, the right posterior cerebellum connects to and shows correlated activity with left-hemisphere language cortices. The cerebellum is crucial for optimizing skill acquisition, and this role in skill learning could improe the effectiveness of rehabilitation following cerebral cortical stroke. To date, no study has performed cerebellar tDCS in people with aphasia. This project will test the hypothesis that enhancing right cerebellar modulation of left frontal cortex will improve aphasia recovery when applied during five days of traditional speech therapy. The effectiveness of right cerebellar tDCS on language functions will be measured in participants with aphasia from left frontal strokes. Participants will receive both real and sham tDCS in a crossover design. To determine the neurobiological mechanism by which cerebellar tDCS affects recovery, structural and functional neuroimaging will measure pre- and post-treatment alterations in cortical and cerebellar activity and cerebro-cerebellar connectivity. TDCS is an inexpensive treatment with potentially powerful therapeutic possibilities. Given the role of the cerebellum in both language and skill acquisition, the right cerebellum offers an innovative site for neuromodulation using tDCS in people with aphasia. This project may produce findings that will impact not only the millions of people living with aphasia, but also those with strokes affecting motor, prefrontal and parietal cortices to which the cerebellum projects. Through the use of neuroimaging, this project will provide information about how the brain changes during this therapeutic intervention, broadening our understanding of the impact of neuromodulation following brain injury. This has far-reaching impact on all neural injury, well beyond the population studied in this proposal.